Alekseyev I-21
The Alekseyev I-21 was a twin-engined, single-seat, jet fighter, designed and produced in the USSR from 1945 to 1948. Development After working as Lavochkin's right hand man during WWII, Semyon Alekseyev was appointed as Chief Director of OKB-21 at Gor'kiy. The Council of the People's Commissars directed Alekseyev (among others) to develop jet fighters using more powerful engines than the captured German examples and their Soviet-built copies. The result of Alekseyev's efforts was the'' ''I-21 (istrebitel, fighter), which was planned to be produced in several variants. The I-21 was a twin-engined all metal single seat jet fighter with straight wings, mid-set on a round streamlined fuselage, and engines mounted in front of the wings at about one third span. The slightly swept tail unit was cruciform in layout with the tailplane set at approximately half-fin spin with slight dihedral. The aircraft's structure was constructed from high strength B-95 aluminum alloy, high-strength steel for highly loaded parts and "Elektron" magnesium alloy for cast fittings. A hydraulically retractable tricycle undercarriage was fitted, using twin wheels for nose and main undercarriages. Hydraullically actuated airbrakes were fitted on either side of the rear fuselage. Construction of the first two airframes began at the end of 1946, with extreme pressure from the Ministry of Aircraft Production to complete initial flight testing by 1 Aug. 1947, to enable the aircraft to take part in the Aviation Day Flypast at Tushino on 18 Aug. 1947. The aircraft was tested as the I-211. Despite pressure from above, the I-211 was unable to participate in the Tushino display. Flight testing started in autumn of 1947, but only six test flights were completed before the I-211 struck a pothole on landing, which collapsed the undercarriage. Reparis were carried out and the opportunity taken to replace the troublesome TR-1 engines with Rolls-Royce derwent V engines. The result was the I-125 which had been in development before the first flight of the I-211. Other modifications were carried out, the most noticeable being the larger engine nacelles. Despite good results from flight testing the I-215 lost out in production orders to the newer generation of swept winged fighters. A third I-21 was built as the I-215D, with a bicycle undercarriage, using wider-diameter paired wheels in a bicycle arragnement, retracting into the fuselage, along with small outrigger wheels under the engine nacelles which retracted into fairings. The main undercarriage of the I-215D also incorporated a kneeling feature which could increase the incidence of the aircraft by 3 degrees. Armament of the I-211 comprised two, three, four, or six cannon depending on the variant. Variants *'I-210' - The initial verison with Tumanskii RD-20 engines. Not proceeded due to availablility of the Lyul'ka TR-1 engines. *'I-211' - The first flyable example completed as the I-211 with Lyul'ka TR-1 engines, rebuilt as the I-215. *'I-211S' - I-211 with swept wing and tail. *'I-215' - The re-built I-211 with Rolls-Royce Derwent V engines and other minor modifications. *'I-215D' - Bicycle undercarriage I-215 built to order of OKB-1. *'I-216' - Proposed "Heavy" fighter version of the I-215 with two 75mm cannon and modified outer wings. Category:USSR Air Force Category:Soviet Military